HashCache: A new way to speed up internet.

Universities in developing countries afford only low-bandwidth connections; individual users receive the equivalent of a fraction of a dial-up connection. To boost the utility of these connections, Pai and his group created HashCache, a highly efficient method of caching, that is, storing frequently accessed Web content on a local hard drive instead of using precious bandwidth to retrieve the same information repeatedly. The process can be implemented in cell phones, laptops or nearly any other hardware.”

HashCache, created by a team of researchers headed by computer science professor Vivek Pai, a computer scientist at Princeton University, features a new data-caching system that stores information more efficiently than current methods. By making internet access more affordable, HashCache has the potential to expand web use in developing regions around the world.

Despite the Web's protean nature, a surprising amount of its content doesn't change often or by very much. But current caching technologies require not only large hard disks to hold data but also lots of random-access memory (RAM) to store an index that contains the "address" of each piece of content on the disk. RAM is expensive relative to hard-disk capacity, and it works only when supplied with electricity--which, like bandwidth, is often both expensive and scarce in the developing world.

HashCache abolishes the index, slashing RAM and electricity requirements by roughly a factor of 10. It starts by transforming the URL of each stored Web "object", an image, graphic, or block of text on a Web page--into a shorter number, using a bit of math called a hash function. While most other caching systems do this, they also store each hash number in a RAM-hogging table that correlates it with a hard-disk memory address. Pai's technology can skip this step because it uses a novel hash function: the number that the function produces defines the spot on the disk where the corresponding Web object can be found. "By using the hash to directly compute the location, we can get rid of the index entirely," Pai says.

This new method for storing Web content could make Internet access more affordable and accessible worldwide, and is currently being field-tested at the Kokrobitey Institute in Ghana and Obafemi Awolowo University in Nigeria.

Thanks for the very interesting post Andy. We sometimes forget that there are others that are not as privilaged as we are so anything that helps others to get connected has got to be a great idea The more we commmunicate the greater understanding there is between all peoples and the less chance of ignorance, prejudice and war